- Saves typing.
\d
- Means digit.
- The equivalent is
[0-9]
\w
- Word character.
- The equivalent is
[a-zA-Z0-9_]
\s
- Whitespace.
- The equivalent is
[\t\r\n]
- Tabs, line returns and line feed.
- The negative of each is:
\D
- Not a digit.
- The equivalent is
[^0-9]
\W
- Not a word character.
- The equivalent is
[^a-zA-Z0-9]
\S
- Not whitespace.
- The equivalent is
[^ \t\r\n]
- Older Unix boxes likely don’t support these. All newer regex engines do support them.
- Caution:
\w
* The equivalent is [a-zA-Z0-9_]
* Underscore is a word character.
- For the underscore, regex is a primary tool used for programmers and an
_ is often used in programming for variable names etc. This is why an underscore is included.
- A hypen is not considered a word character.
- Examples:
/\d\d\d\d/ matches “1984”, but not “text”.
/\w\w\w/ matches “ABC”, “123” and “1_A”./\w\s\w\w/ matches “I am”, but not “Am I”/[\w\-]/ matches any word character or hyphen./[^\d]/ is the same as /\D/ and /[^0-9]/- Caution –>
/[^\d\s]/ is not the same as /[\D\S].
/[^\d\s]/ = NOT digit OR space character.
- Find any one character that is not a digit or space.
/[\D\S]/ = EITHER NOT digit OR NOT space character.
- Example
/\d\d\d\d/ matches “1984”
- Example
/\w/ matches “blue-green paint” (not the “-“ or the whitespace)
- They are not considered word characters.
- To match the hypen as well, we use
/[\w\-]/
- Example:
/[^\d\s]/ only matches “abc” out of “1234 5678 abc”
- Example:
/[\D\S]/ matches everything in “1234 5678 abc” including whitespaces.